U.S. patent number 4,469,595 [Application Number 06/431,156] was granted by the patent office on 1984-09-04 for filter assembly for a spray booth.
This patent grant is currently assigned to Protectaire Systems Company. Invention is credited to Stanley C. Napadow.
United States Patent |
4,469,595 |
Napadow |
September 4, 1984 |
**Please see images for:
( Certificate of Correction ) ** |
Filter assembly for a spray booth
Abstract
A paint spray booth including water wash means for removing
airborne paint particles from air flowing through the booth. A
holding tank at the bottom of the booth collects the water from the
water wash means and a pump recirculates the water from the holding
tank to the water wash means near the top of the booth. A filtering
tank is connected to the holding tank and is located outside the
booth. A pair of filters are disposed in series in the filtering
tank and filter the water as it passes from the holding tank to the
pump. The filters are individually removable from the filter tank
for cleaning and/or replacement so that when one filter becomes
clogged, it can be removed and cleaned while the other filter
continues the filtering process so that there is no interruption in
use of the spray booth.
Inventors: |
Napadow; Stanley C. (Elgin,
IL) |
Assignee: |
Protectaire Systems Company
(Elgin, IL)
|
Family
ID: |
23710726 |
Appl.
No.: |
06/431,156 |
Filed: |
September 30, 1982 |
Current U.S.
Class: |
210/111;
210/167.31; 55/288; 454/55; 55/DIG.46; 118/326; 454/54 |
Current CPC
Class: |
B01D
29/01 (20130101); B05B 14/465 (20180201); B01D
47/022 (20130101); B05B 14/462 (20180201); B01D
35/12 (20130101); B01D 29/56 (20130101); B01D
29/96 (20130101); Y10S 55/46 (20130101) |
Current International
Class: |
B01D
47/02 (20060101); B05B 15/12 (20060101); B01D
29/01 (20060101); B01D 35/00 (20060101); B01D
35/12 (20060101); B01D 29/00 (20060101); B01D
29/56 (20060101); B01D 29/50 (20060101); B01D
29/96 (20060101); B01D 035/08 () |
Field of
Search: |
;210/167,111,119,128
;55/288,242,DIG.46 ;118/326 ;98/115SB |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hruskoci; Peter A.
Assistant Examiner: Cohen; Sharon T.
Attorney, Agent or Firm: Fitch, Even, Tabin &
Flannery
Claims
What is claimed is:
1. In a paint spray apparatus of the type including a booth, means
including a pump for delivering water to an upper portion of said
booth, means for causing said water to flow downwardly in said
booth for washing paint particles from air flowing through said
booth, the improvement comprising a holding tank at the bottom of
said booth for collecting said water arranged to collect paint
particles on the bottom of said holding tank to allow for a
substantial build up of sludge in said holding tank, a filter tank
outside said booth and between said holding tank and said pump, a
water inlet between said tanks allowing water to flow from said
holding tank into the filtering tank to be filtered, a filter
assembly in said filtering tank including a pair of filters
arranged in series and operable to filter said paint particles from
the water flowing from said holding tank into said holding tank a
water inlet to said pump in said filtering tank on the downstream
side of said filters, said filters being individually removable
from outside said filter tank.
2. The improvement of claim 1, said filters being parallel and
spaced from one another.
3. The improvement of claim 2, said filters being inclined in the
direction of flow of water to said pump.
4. The improvement of claim 3, the angle of inclination of said
filters being about 30.degree. .
5. The improvement of claim 1, said filters being slidably disposed
in tracks formed in said intake filter tank.
6. The improvement of claim 1, said filter tank being formed as an
extension of said holding tank.
7. The improvement of claim 1, said filter tank having an open top
and said filters and the water level upstream and downstream of
said filters is exposed to view whereby a drop in the water level
downstream of said filters can be observed to indicate when at
least one of said filters has become clogged.
8. The improvement of claim 1, including indicator means in said
filter tank and responsive to the water level in said filter tank
downstream of said filters to indicate when at least one of said
filters has become clogged.
9. In a paint spray apparatus of the type including a booth, means
including a pump for delivering water to an upper portion of said
booth, means for causing said water to flow downwardly in said
booth for washing paint particles from air flowing through said
booth, a holding tank at the bottom of said booth for collecting
said water arranged to collect paint particles on the bottom
thereof and to allow for a substantial buildup of sludge in said
holding tank holding tank adjacent the holding tank,
one side of the filter tank being open to the holding tank, a water
inlet between said tanks allowing water to flow from said holding
tank into the filtering tank to be filtered
a filter assembly for holding one or more filters in an located at
said open side of said filter tank to filter the water flowing from
said holding tank to said pump, paint particles accumulating on the
holding side of the filters, one of said filters being individually
removable for cleaning while another filter of the filter assembly
is in position to continue the filtering operation while the one
filter is being cleaned.
Description
BACKGROUND OF THE INVENTION
The present invention relates to filters, and more particularly to
a filter assembly for use in filtering recirculating water in a
spray booth.
Spray booths are used for a variety of purposes, for example, for
spray painting articles. One of the problems encountered in spray
booths is that of prevently escape of errant airborne particles. In
paint spray booths, a solid sheet or curtain of water or a water
spray intersects the path of air flowing through the booth and
washes the particles out of the air. A holding tank is provided at
the bottom of the booth to collect the wash water and a pump
recirculates the water from the tank to the top of the booth.
It will be appreciated that the wash water used in these booths
quickly becomes contaminated with the paint particles and it is
necessary to continuously filter the water before redelivery by the
pump to the top of the booth. Standard filtering assemblies include
a screen over an intake pipe forming part of a conduit which
connects the tank to the pump. The intake pipe is located near the
bottom of the tank and because huge amounts of water are
recirculated in this environment, the screen quickly becomes
clogged. To clean the screen, it is necessary to shut down the
booth and empty the water in the tank. This is very expensive not
only because of lost time in operation of the spray booth but also
because the water has chemicals added to it to prevent growth of
algae and to consolidate the paint particles. Water containing
these chemicals cannot be dumped into a sewer but must be sent off
to an expensive disposal system.
The booth cannot be operated with a clogged filter or screen
because the flow of water is reduced thereby reducing the
effectiveness of the water wash system. Furthermore, should the
filter or screen be completely clogged, the pump can overload and
overheat. Therefore, it is desirable to provide a filter assembly
for water wash spray booths which functions to satisfactorily
filter the water and which allows for easy cleaning without
requiring interruption of use of the spray booth and without
requiring frequent disposal of the water.
SUMMARY OF THE INVENTION
The present invention overcomes the problems and disadvantages of
the prior art by providing a filter assembly in a water wash spray
booth which includes a pair of filters arranged in series and
positioned in a filter tank outside the spray booth. The filter
tank is connected to the recirculating pump and receives water from
the holding tank so that the filters remove paint particles from
the water before delivery to the pump. The filter tank is open at
the top and the filters are easily removable so that one of them
can be removed and cleaned while the other continues to filter the
water. Thus, the filter assembly of this invention is operable to
filter the circulating water and is readily adapted to be cleaned
when necessary without interruption of operation of the spray
booth.
Furthermore, the filter tank can be constructed as an extension of
the holding tank and provides that a substantial amount of sludge
can accumulate at the bottom of the holding tank before requiring
that the water be dumped. In addition, the filter assembly of the
present invention is adapted to be used in connection with an audio
or visual indicator which will alert appropriate personnel when the
filter system needs to be cleaned. In this manner, efficient
operation of the spray booth is maintained and damage to the water
pump is avoided.
Additional objects and advantages of the invention will be set
forth in part in the description which follows and in part will be
obvious from the description, or may be learned by practice of the
invention. The objects and advantages of the invention may be
realized and attained by means of the instrumentalities and
combinations particularly pointed out in the appended claims.
The accompanying drawings, which are incorporated in and constitute
a part of this specification, illustrate embodiments of the
invention and, together with the description, serve to explain the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view partly broken away of a paint spray
booth incorporating a water filter assembly according to the
present invention;
FIG. 2 is an enlarged sectional view of the structure of FIG. 1,
taken along the line 2--2 thereof;
FIG. 3 is a sectional view of the structure of FIG. 2 taken along
the line 3--3 thereof and showing the filter assembly
unclogged;
FIG. 4 is a view similar to FIG. 3 and showing one of the filters
after becoming clogged and partially removed pursuant to cleaning;
and
FIG. 5 is a view similar to FIG. 3 showing the filter assembly of
the present invention used with an indicator and with the filter
assembly clogged and requiring cleaning.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will be made in detail to the present preferred
embodiment of the invention, an example of which is illustrated in
the accompanying drawings.
A paint spray booth embodying the present invention is shown in
FIG. 1 and is represented generally by the numeral 11. The booth
includes a front section or work area 13 through which an article
to be sprayed (not shown) is moved. A manually operated or
automatic spray device (not shown) is used to apply paint to the
article, the spray being either electrostatic or a pressurized
airstream of paint particles as will be understood by those skilled
in the art.
In paint spray booths, some of the solid airborne spray particles
do not adhere to the article and it is necessary that these errant
particles be removed from the air. In the spray booth 11, airborne
spray particles which pass the work area 13 enter a first water
wash means 15 and then a second water wash 17 at the rear of the
booth 11. From there, the cleansed air is discharged out a chimney
21 which is connected to a blower or fan (not shown) which serves
to pull the air through the booth.
The first water wash means 15 includes a plurality of spaced
baffles 23 which are vertically mounted in the booth at the back of
the work area 13. Water is caused to cascade downwardly along the
baffles 23 and forms a sheet or curtain of water through which the
airborne paint particles pass. The wash water then falls into a
holding tank 25 at the bottom of the booth. The second water wash
means 17 includes a manifold 27 provided with a plurality of
downwardly facing nozzles 29. Water is sprayed downwardly by the
nozzles 29 and strikes a splash plate 31 and serves to wash paint
particles from the air which escaped the first water wash means 15.
Water from the nozzles 29 is also collected in the holding tank 25.
Water in the tank 25 is recirculated to the first and second water
wash means 15, 17 by a pump 30.
It will be appreciated that a large volume of water is required to
effectively remove the airborne paint particles from the air
passing through the booth. For example, effective performance of
the first water wash means 15 requires at least thirty and as much
as sixty gallons of water per linear foot flowing down the baffles
23. A booth having a baffle system ten feet wide requires a minimum
of 300 gallons of water for the first water wash means alone.
It will also be appreciated that before the water is recirculated
from the holding tank 25 to the pump and the water wash means, it
is necessary that the water be filtered to remove the paint
particles from it. The pump inlet is connected to the holding tank
about two or three inches above the floor of the tank. A typical
installation uses a screen covering the inlet inside the holding
tank to filter the water before delivery to the pump. When the
screen becomes clogged with paint particles, it is necessary to
shut down the spray booth and then empty the water in the holding
tank in order to clean the screen. This is a very expensive
process, as described above, because of lost time in booth
operation and because there are chemicals in the water which do not
allow it to be dumped into the sewer.
In addition, the tank must be emptied when sludge accumulates at
the level of the intake conduit, or approximately three inches from
the floor of the tank. This also requires frequent interruption in
spray booth use and the expensive disposal process discussed
above.
In accordance with the invention, filter means is provided to
filter the water in the holding tank 25 before delivery to the pump
30. This filter means includes two filters arranged in series and
which are individually removable for cleaning and/or replacement
upon becoming clogged. When one filter is removed, the other
continues to filter the water so that there is no interruption in
the operation of the spray booth.
As embodied herein, a filter tank 33 is provided outside the booth
and is connected to the holding tank 25. As shown, the filter tank
33 can be an extension of the holding tank 25 and receives water
from it. The filter tank 33 has an open top and is connected to the
pump 30 by an inlet conduit 35. The pump outlet is connected by
piping 39 to the second water wash means 17 and by piping 41 to the
first water wash means 15. A motor 43 drives the pump 30 as will be
understood by those skilled in the art.
As further embodied herein, a pair of filters 45,47 are positioned
in series in the filter tank 33. The filter 45 is upstream of the
filter 47 in the direction of flow of water to the conduit 35 and
the pump 30. Both filters 45,47 have a screen mesh size which is
capable of trapping substantially all of the paint particles in the
wash water.
The filter tank 33 is has an open top and is provided with slide
tracks 49,51 on opposite sides thereof, which slidably which
receive filters 45,47 respectively. Preferrably, the tracks 49,51
are parallel and spaced as shown and are inclined in the direction
of water flow. Although not critical, an angle of inclination of
about 30 has been found to be desirable. A triangular shaped filler
plate 52 covers the opening at the bottom of filter 45.
Thus, with the filters 45,47 in place as shown in FIG. 2, and by
virtue of the fact that the filter tank 33 is outside the booth 11
and opened at its top, the upstream surfaces of the filters,
particularly the upstream filter 45, is exposed to view as is the
water level in the filter tank 33 both upstream and downstream of
the filters. Visual observance will allow personnel to determine
when sludge has built up on the filters, particularly upstream
filter 45, to a point where it is clogged. When this occurs, the
clogged filter is slid out of the filter tank, cleaned, and slid
back in. While the clogged filter is being cleaned, the other
filter remains in place and continues the filtering process. There
is no interruption to use of the spray booth.
In addition, sufficient clogging of either or both filters 45,47
and continued operation of the pump 30 will cause the level of the
water in the filter tank 33 downstream of the filters 45,47 to
drop, again providing easy recognition of the clogged filter
assembly.
Normal operation of the filter assembly when it is unclogged is
shown in FIG. 3. The holding tank 25 has a normal level of water
with an accumulation of sludge 53 therein. Water is filtered as it
passes filters 45,47, with nearly all of it accumulating on the
upstream side of the upstream filter 45. When sufficient sludge 53
has accumulated on the filter 45, it will be obvious to view and
the filter 45 can be removed for cleaning as shown in FIG. 4.
In addition, when the filter 45 becomes clogged, the water level at
the downstream side of it drops as shown in FIG. 4. Thus, one can
observe both the accumulation of sludge 53 on the filter 45 and the
drop in the water level at the downstream side of the filters and
will become aware that one of the filters must be cleaned.
When one of the filters is removed by sliding it upwardly along its
tracks as is shown in FIG. 4 for filter 45, the filtering system
remains intact with the other filter 47 continuing to perform the
filtering operation. There is no interruption to the filtering
process and therefore no interruption to operation of the spray
booth. Furthermore, there is no need to empty the holding tank 25
to carry out this process and no requirement for expensive disposal
of the chemically treated water. When the filter 45 has been
cleaned, it may be slipped back in place in the tracks 49. When a
sufficient amount of sludge has built up on the filter 47, it too
can be removed and cleaned in a similar fashion. Again, there is no
interruption to the filtering process and no resulting interruption
in the use of the spray booth.
It has been found that the filter system of the present invention
allows a substantial build up of sludge in the holding tank 25
before the water therein must be dumped. For example, one
installation utilizing this invention allows a build up of up to
fourteen inches of sludge on the bottom of the tank 25, whereas in
a similar booth utilizing a screened intake pipes at the holding
tank allows only a three inch build up of sludge on the tank floor.
This significantly reduces the cost of operating the spray
booth.
In the modified embodiment of FIG. 5, indicating means is employed
in the filter tank downstream of the filters and is operable in
response to the level of water in the filter tank downstream of the
filter to indicate when the filter means is clogged. As embodied
herein a float 55 is carried by an arm 57 pivoted to a housing 59
mounted on the filter tank 53. As the water level in the filter
tank 33 downstream of the filters 45, 47 drops, the float 55 also
drops causing the arm 57 to pivot in a clockwise direction as seen
in FIG. 5. When the water level falls to a predetermined level an
audible or visual indicator 61 is actuated advising the appropriate
personnel that at least one of the filters is clogged and must be
cleaned. In all other respects, the structure shown in FIG. 5 is
substantially the same as that described above for FIGS. 1-4.
It will be apparent to those skilled in the art that various
additions, substitutions, modifications and omissions can be made
in the present invention without departing from the scope or spirit
of the invention. Thus, it is intended that the present invention
cover the additions, substitutions, modifications and omissions
provided they come within the scope of the appended claims and
their equivalents.
It will be appreciated that with the present invention, the water
flow and volume of water flowing through the water washes may be
kept more constant than in prior art booths having a filter in the
booth at the pump. That is, in the conventional booth, the clogging
of the filter reduces very substantially the volume of water being
pumped to the water washes so that the efficiency of the scrubbing
of particulates is reduced. The dropping of the water level in the
filter tank provides a warning that was heretofore not available
and therefore results in more timely and more frequent filter
cleaning than with the conventional spray booths particularly
because it is not necessary to stop operation of the booth to clean
the clogging filter.
* * * * *